Core bit plug attaching device



April 10, 1934. E. GARFIELD CORE BIT PLUG ATTACHING DEVICE Filed June 8, 19 35 Fig. 1

L. E. GARFIELD INVENTOR ATTORNEY j Patented Apr. 10, 1934 UNITED STATES PATENT OFFlCE CORE BIT PLUG ATTACHING DEVICE Lewis E. Garfield, Houston, Tex.

Application June 8, 1933, Serial No. 674,869

6 Claims. (01, 255-72) My invention relates to core drills employed in well drilling to obtain a sample of the formation being drilled. It pertains particularly to the means by which the plug for the core bit is temporarily secured in position while the bit is being introduced into the hole.

Where core bit plugs are used with core drills, it is customary to secure them in place when the core drill is lowered into cutting position, by a shear pin or other frangible device connecting the plug directly to the core barrel or to the body of the drill bit. The attachment of the plug to either the bit or to the core barrel is a somewhat diflicult proposition as the body of the drill or the barrel must be drilled to accommodate a plurality of pins extending through to the body of the plug.

It is an object of my invention to attach the core bit plug to the core catcher or to some re- 0 movable part which can be clamped in position in the ordinary assembly of the core barrel in the bit.

v I desire to drop the plug and the ring to which it is attached into a recess in the bit head and 5 secure said ring between the bit head and the lower end of the core barrel, thus eliminating the necessity of a connection between the plug and the bit or core barrel.

- In the drawing herewith Fig. 1 is a fragmental central longitudinal section through a core bit and core barrel with my invention incorporated therein.

Fig. 2 is a transverse section on the plane 2--2 of Fig. 1.

My invention is shown as employed with an ordinary type of scraping or drag core bit. The head 1 of the bit has an interior threaded socket 2 for attachment of the bit to the drill collar 3. The bit has scraping blades 4 thereon, which extend somewhat in advance of the head. As

seen in Fig. 2 there are three blades, the forward cutting face of which is approximately radial.

The interior of the core bit head is recessed or counterbored at 5 to receive .the ring 6 of the core catcher and the lower end of the core barrel 7. The shoulder 8 in the head furnishes a seat against which the ring 6 rests when the core barrel is fixed in operative position by its upper connection with the drill collar, not shown.

The core catcher is of common construction. It has a ring 6, previously noted, to which are attached a plurality of spaced spring fingers 9, curved inwardly at their upper ends to engage the core. Said fingers are shown in Fig. 2 as being held to the ring by rivets 10.

The core bit plug includes an outer sleeve 11 the upper end of which is attached to the plug 12 with a threaded connection 13. Said sleeve is formed with an annular recess 14 on its inner surface adjacent its lower end and a plurality of openings are formed'through the outer wall of. said recess to receive rivets or pins 15 which are extended therethrough so as to connect said sleeve 11 to the core catcher ring 6. These. rivets are of soft or frangible .metal which may be sheared 5 oil when a heavy thrust upon the plug tends to drive it upwardly into the core barrel. The core bit plug 12 projects in advance of the bit so as to engage the bottom of the. hole as the core bit is lowered into cutting position.

It will be understood that when the drill is introduced into the hole the plug will be mounted upon the core catcher as shown in the drawing. The plug body 12 is unscrewed from the sleeve 11 and the rivets 15 are inserted through the sleeve and the core catcher ring. The plug is then inserted into position and the assembled plug and core catcher may then be handled as one piece in assembling the bit and core barrel.

When the tool encounters bottom the plug will stop and the core bit may be thrust down over the plug to shear the pins 15 and the plug will then pass upinto the core barrel ahead of the core as the drilling proceeds. The plug serves to keep mud from entering the core barrel while going into the hole and the core is thus uncontaminated by material remote from the formation being drilled.

The support for the plug upon the core catcher is an improvement which not only makes it possible to cheapen the costs of manufacture but which also enables the operator to assemble the device quickly and securely. The attaching pins 15 are held in position without the necessity of upsetting the ends thereof. The advantages of the device will be clear without further explanation.

What I claim as new is:

1. In a core drill, an annular bit head, an inner recess therein having a lower shoulder, a core catcher adapted to fit within said recess upon said shoulder, a core barrel plug adapted to close the space inside said bit and, core catcher, frangible means connecting said plug and said core catcher, and means to retain said core catcher upon said shoulder.

2. In a core drill, an annular bit head, an inner recess therein having a lower shoulder, a core catcher adapted to fit within said recess upon said shoulder, a core barrel plug adapted to close the space inside said bit and core catcher, frangible means connecting said plug and said core catcher, and a core barrel inside said bit and engageable-with said core catcher to retain said core 5 catcher in position.

passage having a lower shoulder, a ring adapted to seat on said shoulder, a plug fitting within the lower end of said passage, frangible means to secure said plug to said ring and means to retain said ring on said shoulder.

5. The combination of a core bit, a core catcher therein, means to anchor said core catcher in said core bit, a plug, and frangible means connecting said plug and said core catcher.

6. In combination; a core drill, a core catcher, a core barrel adapted to retain said core catcher in said drill, a core bit plug, and frangible means connecting said core bit plug to said core catcher.

- LEWIS E. GARFIELD. 

